66 research outputs found

    HORMONEMEDIATED REGULATION OF CYTOKINES IN PATIENTS WITH ADENOMYOSIS AND UNSUCCESSFUL IVF ATTEMPTS

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    Aim. The study was to evaluate the effect of cytokine dysfunctions on the endometrial implantation potential in patients with adenomyosis and unsuccessful IVF attempts and the possibility of hormone-mediated regulation of the cytokine balance at the pre-gravitational stage. Materials and methods. The study included 90 patients with infertility, an unsuccessful attempt of IVF in the history and diffuse adenomyosis of 1 or 2 degrees. Patients were randomized into two groups: the 1st group consisted of 44 patients (group 1) − no pre-education training was conducted. The second group − 46 patients − pregravid preparation of dienogest (2 mg daily for 3 months before the IVF cycle). Control group (group 3) − 30 healthy fertile women. To assess the implantation potential of the endometrium, initially, and after pre-gravity training, the concentration of LIF, IL1в, IL-6, IL-10, RAIL in cervical mucus was determined.Results. Analysis of the indices in patients with adenomyosis showed a decrease in their implantation potential of the endometrium. It has been revealed that hormone-modulating therapy with dienogest partially neutralizes cytokine regulation defects and leads to a certain increase in the effectiveness of IVF programs.Conclusion. Shows expediency of including dienogest in the pregravide preparation plan for patients with adenomyosis, but for full immunocorrection in pregravidual training in women with adenomyosis 1 and 2 The degree of additional directional immunotropic therapy is probably necessary

    Self-healing polyurethane-polypropylene oxide copolymers for the protection of carbon and glass fiber-reinforced composites

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    Polyurethane-polypropylene oxide block copolymers containing fragments of an adduct capable of self-healing by the Diels-Alder reaction mechanism have been synthesized and studied for the first time. All obtained polyurethane copolymers were characterized by IR spectroscopy. The temperature transitions and thermal stability of copolymer melts were determined by using the methods of differential scanning calorimetry and thermogravimetric analysis. The self-healing effect was confirmed using a thermal cycling procedure on pre-damaged samples of modified polyurethanes and surface morphology studies. The perspective of the work begun on the creation of self-healing protective polyurethane coatings are shown

    Influence of coloring on the properties of epoxy binders and fiberglass rebar based on them

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    At present, polymer composite materials are widely used in the construction and automotive industries, products for which must meet not only operational, but also aesthetic requirements. Since color is one of the most important design elements, much attention is paid to the coloring of structural composites. There is a fairly wide range of different methods for coloring polymer composites, but each method has both advantages and disadvantages. This article discusses two methods for coloring a hot amine-cured epoxy composition, which is used for the manufacture of composite fiberglass reinforcement: by adding pigment and organic dyes to the epoxy composition. It has been found that organic dyes dissolve in all components of the epoxy composition, but become colorless upon heat treatment. When adding an insoluble dispersed pigment, the color remains unchanged even after the thermal curing of the epoxy matrix. The addition of up to 0.5 mass parts of iron oxide pigment (“red FEPREN TP-303”) to the epoxy binder slightly reduces the mechanical strength of the composite and significantly increases its thermal stability

    Alkali resistant epoxy binders for pultrusion

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    Alkali-resistant hot-curing epoxy binders based on ED-20 and new amine hardeners “Amikrost” have been developed, intended for the production of glass-composite fittings for construction purposes. The rheological properties of epoxy compositions were determined, using differential scanning calorimetry and thermogravimetric analysis, the temperature dynamics of the curing process of epoxy compositions and the thermal-oxidative resistance of cured samples were studied. The alkali resistance of cured epoxy compositions and specimens of composite reinforcement in 40% alkali aqueous solution was evaluated. It is shown that the developed amine hardeners provide high alkali resistance of composite reinforcement in comparison with the currently used anhydride hardener iso-MTHPA, which is especially important for reinforcing buried and hydraulic concrete

    Дослідження та обґрунтування параметрів замкових з'єднань паркетних дощок

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    Three-layer parquet boards are becoming increasingly popular on the market of wooden flooring in Ukraine. Demand for flooring is caused by rapid growth of the construction industry, particularly in the residential sector. The purpose of the work is to study and substantiate the design features and operating parameters of parquet boards for consistency with the geometry of the profile, the magnitudes of the differences and gap between the ends of the parquet boards at the 5G-C lock joint. The statistical processing of the experimental studies confirmed the validity of the results obtained and the permissible deviation of the parameters of the boards' geometry in accordance with the established standards. The statistical analysis of the experimental studies on the differences and gap between the ends of the parquet boards at lock joint between adjacent boards during the "4 boards" test showed that a small part of joints does not meet the regulatory requirements. The experimental studies and statistical processing of their data made it possible to detect the deviation of the parameters of parquet boards and to plot graphs for comparing the characteristics of the differences and gap values during the tests "4 boards", "Tongue", "Groove" and with various widths of boards with inserts from HDF and veneer for the 5G-C end joint. As a result of the analysis of comparative graphs, it is established: the change in the magnitude of differences and the size of the gap depends on the type of test used; during the "4 boards" test, the values for the differences and the size of the gap are minimal; the influence of the insert material on the size of the gap and the values of the differences is insignificant; the size of the gap increases during the "Tongue" test, and exceeds the tolerance for boards of 130 mm and 180 mm wide; the differences value increases during the "Groove" test and exceeds the tolerance for boards of 130 mm in width; A gap with a board width of 207 mm has the slightest deviation for all tests. The conducted studies and statistical data processing made it possible to establish deviations of the parameters of the parquet board profile and to construct a polygon and distribution curves, graphs for comparing the characteristics of the differences and the gap size in the "4 boards" tests, at the loads in the tests of "Tongue", "Groove" and with the inserts from HDF and veneer for the 5G-C lock joint. The processing of experimental data showed that the frequency of distribution of the values for the differences between adjacent parquet boards during the "4 boards" tests can be described by a second order polynomial, the frequency of distribution of the gap size between adjacent parquet boards can be described by a logarithmic function. The insignificant percentage of reject items (up to 5 %) with the excess of the differences values is due to inaccurate adjustment of the tool in calibration operations on the thickness of the boards, milling of the longitudinal and transverse profiles and partial wear of the tool. Deviations of the differences values and the gap size for the tests of "Tongue" and "Groove" are within the tolerance field. The obtained results of the study confirmed the fact that parquet boards with veneer and PVC inserts are more reliable in operation and can be used on premises where there is an increased level of loads, temperature and humidity variations (public rooms, assembly halls, gyms, etc.).Встановлено параметри відповідності контролю профілю з'єднання та геометрії паркетних дощок після фрезерування. Виконано статистичний аналіз показників параметрів геометрії паркетних дощок та параметрів контролю сучасного профілю поперечного (торцевого) замкового з'єднання 5G-C відповідно до лекал оптичного проектора та розподілу величин параметрів перепаду і щілини від тестових навантажень. Досліджено показники міцності з'єднання профілю при вертикальних навантаженнях залежно від матеріалу вкладки та положення пластикової вставки. Зроблено практичні висновки згідно з дослідженнями контролю профілю з'єднання 5G-C та дошки загалом після фрезерування в технологічному потоці. Встановлено відповідність значень параметрів при контролі профілю з'єднання та геометрії дошки після фрезерування на проекторі, за шаблоном, за тестами складання і навантаження дощок до нормативних показників та якості. Запропонований перелік заходів щодо економії сировини у виробництві сучасних і традиційних паркетних виробів дасть змогу контролювати питання з раціонального та ефективного використання деревинної сировини, запровадити у виробництво науково обґрунтовані прогресивні норми

    Prospects for the synthesis and application of copolyimides based on tetracarboxylic acid dianhydride mixtures

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    The process of obtaining copolyimides by polycondensation based on 3,6-diaminoacridine, 9,9-bis-(p-aminophenyl)fluorene, dianhydride of 2,2-bis-(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane and dianhydride of 3,3',4,4'-tetracarboxydifenyloxide are described. The main physico-chemical properties of the obtained products are discussed and the prospects for the use of these soluble and fusible products as a polymer base for the preparation of composite materials are shown

    Current trends in the synthesis of soluble and hot-melt polyimides

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    The work is devoted to a review of works published in recent years on the development of the chemical structure of soluble and hot-melt copolyimides, including a brief description of their synthesis and properties

    Selection of antioxidants to improve the thermal-oxidative stability of polyarylates

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    Using the method of thermogravimetric analysis, the selection of synergistic mixtures of antioxidants for the synthesized polyarylate-polysulfone block copolymer F-230/30 with a glass transition temperature of 260°C was made

    Synthesis and study of block copolymer polyarylates

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    In order to reduce the viscosity of a polyarylate melt based on phenolphthalein and terephthalic acid dichloride with a glass transition temperature of 280°C, polyarylate-polysulfone block copolymers with a glass transition temperature of 240 to 260°C capable of processing through a melt at 340°C were synthesized and studied

    Biochemical aspects of magnesium-enhanced bone regeneration

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    Current research is focused on practical implications of magnesium-based implants largely due to their biodegradability and ability to promote bone healing and formation. However, the mechanism underlying the osteogenesis regulation by magnesium is still unclear.We describe cellular and molecular mechanisms underlying the effect of magnesium ions (Mg2+) on bone growth following the device implantation. The presented data demonstrate magnesium-induced activation of canonical Wnt/β-catenin signaling pathway in human bone marrow stromal cells resulting in their differentiation into osteoblasts, osteogenic effect and recovery of bone defects. We describe the role of the molecular mechanisms responsible for osteopromotive properties of Mg2+ and associated with unique transient receptor potential melastatin 7 (TRPM7) cation channels mediating the Mg2+ influx. TRPM7-mediated Mg2+ influx is important for platelet-derived growth factor (PDGF)-induced proliferation, adhesion, and migration of human osteoblasts, as well as for promotion of Mg2+-associated bone regeneration.We discuss the effect of Mg2+ on intracellular signaling processes, expression of the vascular endothelial growth factor (VEGF), hypoxia-inducible factor-2α, and peroxisome proliferator-activated receptor-γ coactivator 1α. Mg2+ can promote bone regeneration by enhancing the production of type X collagen and VEGF by osteogenic cells in bone marrow
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